By about 1910, most of the regions which now comprise the Republic of Indonesia were brought under Dutch rule. Governor-General van den Bosch (1830–3) had established profitability as the main principle of government, and believed that the Dutch should therefore restrict their attentions to Java, Sumatra and Bangka (a source of tin). Nonetheless, from about 1840 onwards Dutch involvement increased throughout the outer islands. There were many reasons for this. Often there were economic motivations, including the protection of inter-insular trade. (The economic developments which followed Dutch expansion are described in Chapter 13.) Often local Dutch officials intervened out of ambition for glory or promotion, despite Batavia s official policy of avoiding further extensions of Dutch authority. Two general considerations applied everywhere. First, to protect the security of areas they already held, the Dutch felt compelled to subdue other regions which might support or inspire resistance movements. Second, as the European scramble for colonies reached its height in the later nineteenth century, the Dutch felt obliged to establish their claims to the outer islands of the archipelago in order to prevent some other Western power from intervening there, even where the Dutch initially had no great interest themselves.